Amish wrote on his MBS launch blog that they started running the MSN Messenger/Smiley Central campaign from end November 2009. At that time, I used to have a subscription to KeywordSpy. If you were to research the keyword "download msn messenger", you'll find that someone else was running this campaign on adwords many months before these guys.
So they basically copied someone else's campaign, made some cash running it for a short period of time and then outed the campaign as part of the MBS launch. With many copycats jumping into the whole messenger/smiley central campaign, they must have killed this other affiliate's cash cow.
Karma?